Cosmetic skin treatment is typically performed by application of heat to a segment of skin to be treated. The heat could be generated by application of Radio Frequency (RF), Intense Pulse Light (IPL), laser radiation, ultrasound or a combination of the above energies. Almost all of the skin treatment energies are applied to the skin by a tool termed applicator or handpiece. For example, applicators configured to apply to the skin a combination of RF and IPL or laser light systems such as the one disclosed in U.S. Pat. No. 6,702,808 to the same assignee and other similar systems. The particular applicator includes a long rectangular light guide placed between two bipolar RF electrodes. Concurrent application to the skin of RF energy and light energy allows addressing of skin layers located at different depth at the same treatment. Heating of the tissue via the different energies is additive, sometimes the sum being greater than the parts. The different energies may enter the skin at different locations. The energies applied to the treated skin segment and in particular light energy, are not distributed uniform across the treated skin or tissue segment. Typically the light energy decreases exponentially as the light passes deeper into tissue while in skin, the RF energy decreases laterally as you move away from the electrode. The combination of the two helps to better homogenize tissue heating. When the applicator is moved across the skin with a single energy source, some of the areas of the skin segment could be over treated and even burned and some of the areas could be undertreated. Because of these differences multiple sources allows reduction of each of the energies and diminishes the danger of skin burning.
The adverse effects caused by application of large amount of heat, particularly light, to the treated skin or tissue segment could be somehow mitigated by concurrent gradient cooling of the treated tissue. Cooling of the tissue segment located in a tissue or skin treatment plane is usually performed by cooling an applicator element being in contact with the skin treatment plane. Methods of applying a cooled fluid spray directly to the tissue or skin treatment plane are also known.
U.S. Pat. Nos. 6,383,176, 6,485,484, 6,666,856, 7,465,307, and 8,474,463 disclose different skin treatment applicators.